Controller and controlling method for internal combustion engine

ABSTRACT

A base engine torque generated with an estimated intake air amount is estimated. An engine torque is corrected by correcting an ignition timing based on a difference between a required engine torque and the base engine torque. A torque correction amount is calculated based on a correction amount of the ignition timing. An actual engine torque is estimated based on the calculated torque correction amount and the base engine torque. A permitted component driving torque is a difference between the actual engine torque and the required vehicle driving torque. A component is controlled based on the permitted component driving torque.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.11/589,999 filed Oct. 31, 2006 which is based on Japanese PatentApplications No. 2005-317844 filed on Nov. 1, 2005, and No. 2005-336470filed on Nov. 22, 2005, the disclosure of which are incorporated hereinby reference. This application is also related to U.S. patentapplication Ser. No. 11/441,226 filed May 26, 2006.

FIELD OF THE INVENTION

The present invention relates to a controller for an internal combustionengine, and a controlling method for an internal combustion engine. Theinternal combustion engine is provided with function in which drivingtorque of components, which is driven by an engine torque, iscontrolled. The engine torque represents an output torque of the engine.

BACKGROUND OF THE INVENTION

A vehicle is equipped with components which are driven by engine. Forexample, the engine is equipped with an alternator, a compressor for airconditioner, a high-pressure pump for increasing fuel pressure, an oilpump, a motor generator, and the like. Since, these components aredriven by the engine, a fluctuation in engine speed and/or unintentionalacceleration/deceleration of the vehicle may be arose when drivingtorque of the components are rapidly changed.

Japanese Patent No. 2709061 shows that an intake air amount and anignition timing are corrected at a time of switching of anair-conditioner in order to restrict the fluctuation in idle speed dueto the switching of air-conditioner.

Generally, since the engine torque is controlled based on a throttleposition (intake air amount) or a fuel injection amount, a responsedelay exists in an intake system. That is, there is time lag between atime when the throttle position is varied and a time when the enginetorque is changed.

In the above. Japanese Patent, both intake amount and ignition timingare corrected when the air-conditioner is turned on/off. The correctionof the engine torque based on the correction of the ignition timingcauses no response delay unlike the correction of the intake air amount.The torque correction amount which is delayed by the intake air amountcorrection is ensured by the correction of the ignition timing.

However, the torque which can be ensured by correcting the ignitiontiming is limited. When the ignition timing is close to a knocking limitor a stable combustion limit, a permitted correcting range of theignition timing is relatively narrow and the torque correction amount issmall. Thereby, when the driving torque of components are rapidlychanged, even if both intake air amount and ignition timing arecorrected, the torque correction amount runs shortage relative to therapid change in driving torque of the components, which may cause thefluctuation in engine speed and the acceleration/deceleration of thevehicle.

The above fluctuation in engine speed and the acceleration/decelerationof the vehicle can be restricted if the increased (decreased) drivingtorque of the components are canceled by the increased (decreased)engine torque. In this case, the increased/decreased amount of drivingtorque of components may be estimated based on control parameters of thecomponents. However, the estimated value of the increased/decreasedamount of driving torque of the components must includes some errors dueto a individual productive dispersion or an aging thereof. Furthermore,the engine torque command value may be deviated from the actual enginetorque due to such a dispersion and aging.

Even if the increased amount (decreased amount) of the driving torque ofthe components and the increased amount (decreased amount) of the enginetorque are controlled in synchronization with each other, the torqueerror cannot be avoided. The above fluctuation in engine speed andunintentional acceleration/deceleration cannot be restricted enough.

SUMMARY OF THE INVENTION

The present invention is made in view of the foregoing matter and it isan object of the present invention to provide an engine controller andengine control method which can restrict fluctuation in engine speedand/or unintentional acceleration/deceleration when driving torque ofcomponents are rapidly changed.

According to a controller of the present invention, including: acomponent torque calculating means for calculating a required componentdriving torque; an engine torque calculating means for calculating arequired engine torque which is obtained by adding a required vehicledriving torque to the required component driving torque; an intake aircalculating means for calculating a required intake air amount; anintake air controlling means for controlling an intake air amount basedon the required intake air amount; a base engine torque estimating meansfor estimating an actual intake air amount, and estimating a base enginetorque; a torque correction means for correcting the engine torque bycorrecting an ignition timing based on a difference between the requiredengine torque and the base engine torque; an actual engine torqueestimating means for calculating a torque correction amount based on acorrection amount of the ignition timing, and estimating an actualengine torque based on the calculated torque correction amount and thebase engine torque; a permitted torque calculating means for calculatinga difference, as a permitted component driving torque, between theactual engine torque and the required vehicle driving torque; and acomponent controlling means for controlling the component based on thepermitted component driving torque.

According to another aspect of the invention, a controller including: acomponent controlling means for controlling a component; a torquecorrecting means for correcting a control error of an output torque ofthe engine; a learning means for learning a torque correction amount,while a torque necessary to drive the component is varied in a casedwhere a predetermined torque correction amount learning condition isestablished, and an engine controlling means for controlling the outputtorque of the engine by correcting a torque command value based on alean-value of the torque correction amount.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features, and advantages of the presentinvention will become more apparent from the following detaileddescription made with reference to the accompanying drawings, in whichlike parts are designated by like reference number and in which:

FIG. 1 is a schematic block diagram showing an engine control systemaccording to a first embodiment;

FIG. 2 is a block diagram for explaining function of a control systemaccording to the first embodiment;

FIG. 3 is a flowchart showing a cooperative control between analternator and an engine;

FIG. 4 is a time chart for explaining a control according to the firstembodiment;

FIG. 5 is a block diagram for explaining function of a control systemaccording to a second embodiment;

FIG. 6 is a schematic block diagram showing an engine control systemaccording to a third embodiment;

FIG. 7 is a time chart showing a control of torque correction amountlearning process;

FIGS. 8A and 8B are charts showing torque correction amount learningmaps;

FIG. 9 is a time chart showing a control after torque correction amountis learned;

FIG. 10 is a flow chart showing a cooperative control; and

FIG. 11 is a flow chart showing the cooperative control.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described hereinafter withreference to the drawings.

First Embodiment

FIG. 1 is a schematic view showing an engine control system. Each deviceof air system, fuel injection system and ignition system of an engine 11is controlled by an engine controller 13 which is included in acontrolling apparatus 12. The controlling apparatus 12 includes avehicle controller 14, an alternator controller 15, and a power sourcecontroller 16. These controllers are electrically connected with eachother.

The vehicle controller 14 calculates a required vehicle driving torque,which represents an engine torque necessary for driving the vehicle. Asignal indicative of the required vehicle driving torque is transmittedto the engine controller 13.

The alternator controller 15 controls electric current generated by analternator 17 by controlling electric current applied to filed coils ofthe alternator 17 based on a permitted power generation torque(permitted components driving torque)

The power source controller 16 is electrically connected to thealternator controller 15 and load controllers 20 a, 20 b. The loadcontrollers 20 a, 20 b control electric loads 19 a, 19 b. The powersource controller 16 detects conditions of the electric load 19 a, 19 b(consumption current of electric load) and a charging condition of abattery 21 to calculate a generating current which is required to thealternator 17. This generating current is referred to as arequired-generate-current (RGC) hereinafter. Furthermore, the powersource controller 16 calculates a required-power-generation-torque todrive the alternator 17 according to the RGC. Thisrequired-power-generation-torque is referred to as the RPGT,hereinafter.

These four controllers 13-16 can be comprised of four computers (ECU) orsingle computer.

Referring to FIG. 2, a cooperative control of the alternator 17 and theengine 11 will be described hereinafter. The engine controller 13 iscomprised of a required engine torque calculator 31, a required intakeair amount calculator 32, an intake air amount controller 33, anin-cylinder air amount estimator 34, a base engine torque estimator 35,a torque corrector 36, an ignition timing corrector 37, an actual enginetorque estimator 38, and a permitted power generation torque calculator39.

The required engine torque calculator 31 calculates a required enginetorque which is derived by adding the required vehicle driving torque tothe RPGT.

The required intake air amount calculator 32 calculates an intake airamount which is necessary to generate the required engine torque. Theintake air amount controller 33 controls a throttle position of anelectric throttle apparatus 40 according to the required intake airamount.

The in-cylinder air amount estimator 34 estimates an actual air amountwhich is introduced into a cylinder by inputting a value of the requiredintake air into a intake system model. This intake system modelsimulates behavior of intake air which is passed through the throttlevalve and is introduced into the cylinder. The base engine torqueestimator 35 estimates the engine torque with the estimated in-cylinderair amount, which is referred to a base engine torque. Furthermore, thebase engine torque estimator 35 estimates the base engine torqueconsidering the ignition timing and/or the fuel injection amount. Thatis, since the in-cylinder air amount, the ignition timing, and the fuelinjection amount are important factors to change the engine torque, thebase engine torque can be accurately estimated based on these factors.

The torque corrector 36 calculates a difference between the requiredengine torque and the base engine torque. The ignition timing corrector37 calculates a correction amount of the ignition timing based on thedifference and corrects the ignition timing to correct the enginetorque. The torque corrector 36 is provided with an ignition correctionguard (not shown) which sets a correction limit of the ignition timingaccording to the engine driving condition. The torque corrector 36 setsa correction amount of the ignition timing in such a manner that thetorque correction amount is brought to be close to the difference.

The actual engine torque estimator 38 estimates the actual engine torquewhich is generated at the next calculation timing by adding the torquecorrection amount to the base engine torque. The permitted powergeneration torque calculator 39 calculates a difference between theestimated actual engine torque and the required vehicle driving torqueas the permitted power generation torque (permitted component drivingtorque).

The alternator controller 15 controls electric current generated by thealternator 17 by controlling electric current applied to filed coils ofthe alternator 17 based on a permitted power generation torquecalculated by the permitted power generation torque calculator 39.

The cooperative control described above is performed by executing acooperative control program shown in FIG. 3. This cooperative controlprogram is executed every predetermined period (for example, 8 msinterval) while the engine is ON. In step 101, the power sourcecontroller 16 calculates the RGC based on the operation condition, suchas consumption current, of the electric loads 19 a, 19 b, and sendssignal indicative of the RGC to the alternator controller 15.

In step 102, the alternator controller 15 calculates the RPGT by use ofthe alternator model. The alternator model calculates the powergeneration torque based on the RGC, the alternator speed, and the powersource voltage. In step 103, the signal indicative of the RPGT istransmitted to the engine controller 13.

In step 104, the engine controller 13 calculates the required enginetorque which is a total of the RPGT and the required vehicle drivingtorque. In step 105, the engine controller 13 calculates the intake airamount which is necessary to generate the required engine torque. Instep 106, the engine controller 13 estimates the actual air amount whichis sucked into the cylinder by inputting the required intake air amountinto the intake air system model which simulates a delay of response inthe intake air system. Then, the engine controller 13 estimates the baseengine torque.

In step 108, the engine controller 13 calculates a range in whichignition timing can be established from a map. This range corresponds tothe correction limit of the ignition timing.

In step 109, the engine controller 13 calculates the difference betweenthe required engine torque and the base torque. Base on this difference,the correction amount of the ignition timing is determined so that thetorque correction amount, which is obtained by correction of theignition timing within the correction limit, is brought to be close tothe difference. In step 110, the engine controller 13 sends signalsindicative of the throttle position and the ignition timing to obtainthe required engine torque to the engine 11.

In step 111, the engine controller 13 estimates the actual engine torquewhich can be realized in the next calculation timing by adding thetorque correction amount to the base engine torque. In step 112, theengine controller 13 calculates the permitted power generation torquewhich is a difference between the actual engine torque and the requiredvehicle driving torque. In step 113, the engine controller 13 sendssignals indicative of the permitted power generation torque to thealternator controller 15.

In step 114, the alternator controller 15 calculates a command powergeneration current corresponding to the permitted power generationtorque. In step 115, the alternator controller 15 controls the controlcurrent (magnetic current) to the alternator 17.

Operations and advantages of the first embodiment will be describedbased on a time chart shown in FIG. 4. In FIG. 4, the RGC is stepwiseincreased at a time of t1.

As shown in FIG. 4, when the RGC is stepwise increased at the time oft1, the RPGT, the required engine torque, and the required intake airamount (throttle position) are also stepwise increased. However, aresponse delay is generated in the intake system until the variation inthrottle position appears as the variation in engine torque. Theresponse delay represents a time delay until the intake air passedthrough the throttle valve is introduced into the cylinder. Thevariation in engine torque represents a variation in in-cylinder airamount.

The ignition timing is corrected considering the response delay in theintake system at the time of t1. However, the torque ensured bycorrecting the ignition timing is limited. Furthermore, in a case wherethe engine is driving with the ignition timing which is close to aknocking limit or a stable combustion limit, the permissible correctionrange of the ignition timing is rather narrow, and the correction amountof torque is rather small by correcting the ignition timing. Thus, whenthe RGC (RPGT) is rapidly increased, the correction amount of torqueruns shortage relative to the rapid increment of the RPGT even if theignition timing is corrected with the intake air amount.

According to the first embodiment, the in-cylinder air amount isestimated considering the response delay in the intake system, and thebase engine torque is estimated according to the estimated in-cylinderair amount. The ignition timing is corrected based on the differencebetween the required engine torque and the base engine torque. Thecorrection amount of torque is calculated by correcting the ignitiontiming. The actual engine torque is estimated by adding the correctionamount of torque to the base engine torque. The difference between theestimated actual engine torque and the required vehicle driving torqueis calculated as the permitted power generation torque by which thealternator 17 is driven. Thus, even if the RGC or the RPGT is rapidlychanged, the alternator is driven by the permitted power generationtorque to drive the vehicle at the required vehicle driving torque. Thatis, unintentional acceleration or deceleration of the vehicle can beavoided when the RGC or the RPGT is rapidly changed.

Furthermore, according to the first embodiment, the permitted powergeneration torque is brought to be close to the RPGT, so that theresponsiveness with respect to the RPGT can be enhanced in the range ofthe ignition timing correction limit.

Second Embodiment

In a case of a direct injection engine, the engine torque can becorrected by correcting the fuel injection amount. Referring to FIG. 2,a second embodiment will be described hereinafter.

A torque corrector 36 a corrects the fuel injection amount by use of afuel injection amount corrector 37 a based on a difference between therequired engine torque and the base engine torque. The torque corrector36 a calculates the torque correction amount based on the correctionamount of the fuel injection amount. An actual engine torque estimator38 estimates the actual engine torque which can be realized in the nextcalculation timing by adding the torque correction amount to the baseengine torque. A permitted power generation torque calculator 39calculates a difference between the actual engine torque and therequired vehicle driving torque. This difference corresponds to thepermitted power generation torque. The alternator 17 is driven with thispermitted power generation torque. Thereby, in the direct injectionengine, even if the fuel injection amount is corrected at a time whenthe driving torque of the alternator 17 is rapidly changed, the vehicleis driven with the required vehicle driving torque, so thatunintentional acceleration or deceleration of the vehicle can beavoided.

A fuel correction guard can be provided to establish a correction limitof the fuel injection amount, which is set by the torque corrector 37 a.The correction amount of the fuel injection amount can be set in such amanner that the torque correction amount is brought to be close to thedifference between the required engine torque and the base enginetorque. The responsiveness with respect to the RPGT can be enhanced inthe range of the ignition timing correction limit.

In the second embodiment shown in FIG. 5, the required engine torquecalculator 31, the required intake air amount calculator 32, the intakeair controller 33, the in-cylinder air amount estimator 34, the baseengine torque estimator 35, the actual engine torque estimator 38 andthe permitted power generation torque calculator 39 have the samefunction as those in the first embodiment. The engine torque can becorrected by correcting the fuel injection timing and the fuel injectionamount.

The component which is cooperative controlled is not limited to thealternator 17. A compressor for air conditioner, a compressor for powersteering, or a motor generator can be used as the component.

Third Embodiment

Referring to FIG. 6, a third embodiment will be described hereinafter.In the third embodiment, the same parts and components as those in thefirst embodiment are indicated with the same reference numerals and thesame descriptions will not be reiterated.

The engine controller 13 includes a torque corrector 18, which correctscontrol error of the engine torque. The engine controller 13 and thealternator controller 15 function as a torque correction amount learningunit 22. When a torque correction amount learning condition isestablished, the unit 22 changes torque, which is necessary to drive thealternator 17, by control current and learns the torque correctionamount corrected by the torque corrector 18. This learn-value is storedin a backup RAM 23. The engine controller 13 corrects a torque commandvalue transmitted from the vehicle controller 14 based on thelearn-value, and controls the engine torque.

When the driving torque of the alternator 17 is rapidly changed whilethe engine is running, it causes a fluctuation of the engine speed orunintentional acceleration or deceleration of the vehicle.

When the increasing amount (or decreasing amount) of the powergeneration torque is cancelled by the increasing amount (or decreasingamount) of the engine torque by synchronization with each other, thefluctuation of the engine speed and unintentional acceleration ordeceleration can be restricted.

The increase and decrease amount of the power generation torque can beestimated from a variation amount in control current of the alternator17. However, individual productive dispersion or aging of the alternator17 generates errors of the estimated value of the increase and decreaseamount of the power generation torque. Furthermore, the engine torquecommand value and the actual engine torque include errors.

Therefore, the fluctuation of the engine speed and the unintentionalacceleration or deceleration cannot be restricted enough unless theerror of torque is corrected.

According to the present embodiment, the torque error is learned, andthe torque command value is corrected based o the learn-value. Referringto FIG. 7, the learning method of the torque error is describedhereinafter.

At a time of t1 in which a torque correction amount learning conditionis established, the RGC is increased by a predetermined value and theRPGT is increased by a predetermined value. Thereby, the command powergeneration current (control current of the alternator 17) and the powergeneration torque are changed in synchronization with each other in alearn-period of the torque correction amount. When the variation inpower generation torque per a control period is excessively large, thefluctuation in engine speed and the acceleration and deceleration of thevehicle becomes large.

In the present embodiment, the RPGT is gradually increased so that thevariation in power generation torque is restricted, whereby thevariation in engine speed and the variation in acceleration anddeceleration speed are limited within a predetermined range.

During learn-period of correction amount of torque, the RPGT isgradually increased to set the increased RPGT as the permitted powergeneration torque and to gradually increase the torque command value ofthe engine 11 in synchronization with the permitted power generationtorque. That is, the increasing amount of the torque command value in acontrol period is equal to the increasing amount of the permitted powergeneration torque in a control period.

As described above, the torque command value of the engine 11 isgradually increased in synchronization with the permitted powergeneration torque, and the correction amount of torque, which isnecessary to make the engine speed consistent with the target enginespeed, is calculated. This correction amount of torque is stored in thebackup RAM 23 as the learn-value.

The learning process is repeated changing the power generation currentto make a three-dimensional map as shown in FIGS. 8A and 8B. The powergeneration current and the engine torque are parameters in this map.Furthermore, such maps are made every engine speed. FIG. 8A is a map ina case that the engine speed is 650 rpm, and FIG. 8B is a map in a casethat the engine speed is 550 rpm. The power generation current, theengine torque, and the engine speed can be parameters of the map.

After the correction amount of torque is learned, the torque commandvalue is corrected based on the learn-value to control the enginetorque, as shown in FIG. 4. For example, at a time of t2 in FIG. 4, whenthe RGC and the RPGT are stepwise increased, the torque command value isalso stepwise increased. This torque command value is corrected based onthe learn-value to control the engine torque (Corrected torque commandvalue=Pre-corrected torque command value−Learn-value). Considering aresponse delay of actual engine torque, the command power generationcurrent is varied with a predetermined delay with respect to a variationin RGC. The permitted power generation torque is varied with apredetermined delay with respect to the RPGT.

The cooperative control of the engine 11 and the alternator 17 areperformed according to the cooperative control program shown in FIGS. 10and 11. This program is executed in a predetermined period (for example,8 ms period) while the engine is running. In step 1101, the alternatorcontroller 15 calculates the RGC based on the operation condition of theelectric loads 19 a, 19 b and the charging condition of the buttery 21.

In step 1102, the alternator controller 15 calculates the RPGT by use ofan alternator model. In step 1103, the alternator controller 15 sendssignals indicative of the RPGT and the RGC to the engine controller 13.

In step 1104, it is determined whether a torque correction amountlearning condition is established based on following conditions.

-   -   (1) An idle speed limit condition is established.    -   (2) The learn-value in learning area corresponding to the engine        speed, the engine torque, and the power generation current has        not been updated for a predetermined time period.

When both of the above conditions are satisfied, the torque correctionamount learning condition is established. When at least one of the aboveconditions is not satisfied, the learning condition is not established.

When the answer is Yes in step 1104, the procedure proceeds to step 1112of FIG. 11 to learn the torque correction amount. In step 1112, the RPGTis gradually changed. In step 1113, the engine controller 13 sends thetorque command value to the engine 11 in order to generate the RPGTwhich has gradually changed. The engine torque is brought to be thetorque command value by controlling at least one of the intake airamount, the fuel injection amount, the fuel injection timing, and theignition timing.

In step 1114, the engine controller 13 estimates the engine torque whichwill be generated after predetermined calculation timing, and calculatethe permitted power generation torque, which is able to supplied to thealternator 17. In step 1115, this permitted power generation torque istransmitted to the alternator 15.

In step 1116, the power generation current corresponding to thepermitted power generation torque is calculated as the command powergeneration current. In step 1117, the control current of alternator 17is controlled so that the alternator generates the electric currentcorresponding to the command power generation current.

In step 1118, the variation in engine speed caused by a change irequired power generation torque is calculated, and a correction amountof the engine torque is calculated, which is necessary to bring thecurrent engine speed to be consistent with the target engine speed. Thiscorrection amount of the engine torque corresponds to the torque errordue to the individual dispersion or aging.

In step 1119, it is determined whether an absolute value of the torquecorrection amount ATCA is smaller than a predetermined value TC0. Whenthe answer is No, the procedure proceeds to step 1121 in which it isdetermined that the learn-value is abnormal to end the program. Thereby,an erroneous leaning of the torque correction amount is prevented toenhance a reliability of the torque learn-value, and a diagnosis of thesystem can be performed.

When the answer is Yes, the procedure proceeds to step 1120 in which thelearn-value of torque correction amount is updated with the correctionamount calculated in step 1118.

When the answer is No in step 1104, the procedure proceeds to step 1105in which the learn-value of the torque correction amount is read. Thislearn-value of the torque correction amount is stored in a learn-regioncorresponding to the current engine speed, the engine torque, and thepower generation current. When no learn-value is learned in thislearn-region, an initial value (for example, 0) is learned as alearn-value of the torque correction amount.

In step 1106, the engine controller 13 sends a torque command value tothe engine 11 in order to generate the RPGT, whereby the engine torqueis controlled to the torque command value.

In step 1107, the engine controller 13 estimates an engine torque whichis realized after a predetermined calculation timing, considering aresponse delay of the engine 11. A difference between the estimatedengine torque and the torque necessary to drive the vehicle iscalculated as the permitted power generation torque. In step 1108, thepermitted power generation torque is transmitted to the alternatorcontroller 15.

In step 1109, the power generation current corresponding to thepermitted power generation torque is calculated as the command powergeneration current. In step 1110, the control current of the alternator17 (field current) is controlled to generate the electric currentcorresponding to the command power generation current.

According to this embodiment, when the torque correction amount learningcondition is established, the driving torque of the alternator 17 ischanged and the torque correction amount is learned as the torque errorto control the engine torque. Thus, even if the torque error exists, thetorque command value (RPGT) can be corrected by the torque error, sothat a fluctuation in engine speed can be restricted due to a rapidchange in the driving torque of the alternator 17.

In a case that the torque correction amount is learned while the engineis running, the engine torque can be feedback-corrected based on avehicle speed or acceleration/deceleration of the vehicle to learn thetorque correction amount. For example, in a vehicle provided with acruise control system, the torque correction amount can be learnedduring a constant speed driving.

In the present embodiment, since the torque correction amount is learnedevery learn-region corresponding to the engine speed, the engine torque,the generating current, the torque correction amount is preciselylearned every engine driving condition and generating current of thealternator 17.

The present invention is not limited to a structure in which thelearn-region is divided by three parameters, such as the engine speed,the engine torque, and the generating current. The learn-region can bedivided by one or two parameters. Alternatively, the learn-region can bedivided by four parameters. The learn-region may not be divided to learnsingle torque correction amount.

According to the present embodiment, since the RPGT is gradually changedduring a learn-period of the torque correction amount, the fluctuationin engine speed and/or the acceleration/deceleration of the vehicle canbe restricted. That is, the variation in the RPGT during thelearn-period is controlled in such a manner that the variation in enginespeed and the variation in acceleration/deceleration are within apredetermined range. This control is executed during a learn-period.After learning, this control is terminated.

1. A controller for a direct injection engine equipped with a componentdriven by the engine, comprising: a component torque calculating meansfor calculating a required component driving torque which is required todrive the components according to a required value; an engine torquecalculating means for calculating a required engine torque which isobtained by adding a required vehicle driving torque to the requiredcomponent driving torque, the required vehicle driving torquerepresenting an engine torque which is required to drive a vehicle; anintake air calculating means for calculating a required intake airamount which is necessary to generate the required engine torque; anintake air controlling means for controlling an intake air amount basedon the required intake air amount; a base engine torque estimating meansfor estimating an actual intake air amount which is introduced into acylinder, and estimating a base engine torque which is generated withthe estimated intake air amount; a torque correction means forcorrecting the engine torque by correcting a fuel injection amount basedon a difference between the required engine torque and the base enginetorque; an actual engine torque estimating means for calculating atorque correction amount based on a correction amount of the fuelinjection amount, and estimating an actual engine torque based on thecalculated torque correction amount and the base engine torque; apermitted torque calculating means for calculating a difference, as apermitted component driving torque, between the actual engine torqueestimated by the actual engine torque estimating means and the requiredvehicle driving torque; and a component controlling means forcontrolling the component based on the permitted component drivingtorque.
 2. The engine controller according to claim 1, furthercomprising a guard means for setting a limit of a fuel injection amountcorrection, which is executed by the torque correction means, based on arange of an air-fuel ratio which is permitted under an engine drivingcondition, wherein the torque correction means sets a correction amountof the fuel injection amount in such a manner that the torque correctionamount is brought to be close to the difference between the requiredengine torque and the base engine torque within the limit of the fuelinjection amount correction.
 3. The engine controller according to claim1, wherein the component is at least one of a alternator, a compressorfor air-conditioner, a compressor for power steering, and a motorgenerator.
 4. The engine controller according to claim 1, wherein thebase engine torque estimating means estimates the base engine torquebased on a estimated intake air amount which is introduced into acylinder and an ignition timing and/or the fuel injection amount whichare predetermined based on the engine driving condition.
 5. A controllerfor an internal combustion engine, comprising: a component controllingmeans for controlling a component, which is driven by the internalcombustion engine; a torque correcting means for correcting a controlerror of an output torque of the internal combustion engine; a learningmeans for learning a torque correction amount, which is determined bythe torque correcting means, while a torque necessary to drive thecomponent is varied in a cased where a predetermined torque correctionamount learning condition is established, and an engine controllingmeans for controlling the output torque of the internal combustionengine by correcting a torque command value based on a lean-value of thetorque correction amount.
 6. The controller for an internal combustionengine according to claim 5, further comprising a memory means forstoring the learn-value of the torque correction amount.
 7. Thecontroller for an internal combustion engine according to claim 5,wherein the component is at least one of an alternator, a compressor forair-conditioner, a compressor for power steering, and a motor generator.8. The controller for an internal combustion engine according to claim5, wherein the engine controller controls the output torque of theinternal combustion engine by adjusting at least one of an intake airamount, a fuel injection amount, a fuel injection timing, and anignition timing.
 9. The controller for an internal combustion engineaccording to claim 5, wherein the torque correcting meansfeedback-corrects the output torque of the internal combustion enginebased on a speed of the internal combustion engine.
 10. The controllerfor an internal combustion engine according to claim 5, wherein thetorque correcting means feedback-corrects the output torque of theinternal combustion engine based on a speed of a vehicle or anacceleration/deceleration speed of a vehicle.
 11. The controller for aninternal combustion engine according to claim 5, wherein the torquecorrecting means learns the torque correction amount every enginedriving condition and/or every control condition of the component. 12.The controller for an internal combustion engine according to claim 5,wherein the torque correcting means restricts a variation in drivingtorque of the component at a time of learning the torque correctionamount in such a manner that a variation in the engine speed orvariation in acceleration/deceleration speed of a vehicle is within apredetermined value.
 13. The controller for an internal combustionengine according to claim 5, wherein the torque correcting means changesthe driving torque of the component gradually at a time of learning thetorque correction amount.
 14. The controller for an internal combustionengine according to claim 5, further comprising a fail determining meansfor determining that the learn-value is abnormal when the learn-value ofthe torque correction amount is out of a predetermined range.
 15. Acontrolling method for an internal combustion engine equipped with acomponent driven by the internal combustion engine, comprising:calculating a required component driving torque which is required todrive the components according to a required value; calculating arequired engine torque which is obtained by adding a required vehicledriving torque to the required component driving torque, the requiredvehicle driving torque representing an engine torque which is requiredto drive a vehicle; calculating a required intake air amount which isnecessary to generate the required engine torque; controlling an intakeair amount based on the required intake air amount; estimating an actualintake air amount which is introduced into a cylinder, and estimating abase engine torque which is generated with the estimated intake airamount; correcting the engine torque by correcting an ignition timingbased on a difference between the required engine torque and the baseengine torque; calculating a torque correction amount based on acorrection amount of the ignition timing, and estimating an actualengine torque based on the calculated torque correction amount and thebase engine torque; calculating a difference, as a permitted componentdriving torque, between the actual engine torque and the requiredvehicle driving torque; and controlling the component based on thepermitted component driving torque.
 16. The engine controlling methodaccording to claim 15, further comprising setting a limit of an ignitiontiming correction according to an engine driving condition, wherein acorrection amount of the ignition timing is set in such a manner thatthe torque correction amount is brought to be close to the differencebetween the required engine torque and the base engine torque within thelimit of the ignition timing correction.
 17. A controlling method for adirect injection engine equipped with a component driven by the engine,comprising: calculating a required component driving torque which isrequired to drive the components according to a required value;calculating a required engine torque which is obtained by adding arequired vehicle driving torque to the required component drivingtorque, the required vehicle driving torque representing an enginetorque which is required to drive a vehicle; calculating a requiredintake air amount which is necessary to generate the required enginetorque; controlling an intake air amount based on the required intakeair amount; estimating an actual intake air amount which is introducedinto a cylinder, and estimating a base engine torque which is generatedwith the estimated intake air amount; correcting the engine torque bycorrecting a fuel injection amount based on a difference between therequired engine torque and the base engine torque; calculating a torquecorrection amount based on a correction amount of the fuel injectionamount, and estimating an actual engine torque based on the calculatedtorque correction amount and the base engine torque; calculating adifference, as a permitted component driving torque, between the actualengine torque and the required vehicle driving torque; and controllingthe component based on the permitted component driving torque.
 18. Theengine controlling method according to claim 17, further comprisingsetting a limit of a fuel injection amount correction based on a rangeof an air-fuel ratio which is permitted under an engine drivingcondition, wherein a correction amount of the fuel injection amount isset in such a manner that the torque correction amount is brought to beclose to the difference between the required engine torque and the baseengine torque within the limit of the fuel injection amount correction.19. The engine controlling method according to claim 15, wherein thecomponent is at least one of a alternator, a compressor forair-conditioner, a compressor for power steering, and a motor generator.20. The engine controlling method according to claim 17, wherein thecomponent is at least one of a alternator, a compressor forair-conditioner, a compressor for power steering, and a motor generator.21. The engine controlling method according to claim 15, wherein thebase engine torque is estimated based on a estimated intake air amountwhich is introduced into a cylinder and the ignition timing and/or afuel injection amount which are predetermined based on the enginedriving condition.
 22. The engine controlling method according to claim17, wherein the base engine torque is estimated based on a estimatedintake air amount which is introduced into a cylinder and an ignitiontiming and/or the fuel injection amount which are predetermined based onthe engine driving condition.